MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
JANUARY, 2001
(For general comments about the nature of these summaries, as well as
information on how to download the tabular cyclone track files, see
the Author's Note at the end of this summary.)
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JANUARY HIGHLIGHTS
--> South Indian Ocean active--rest of Southern Hemisphere quiet
--> Two non-tropical (possibly hybrid) LOWs trigger widespread
severe weather in eastern Australia
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***** Feature of the Month for January *****
TROPICAL CYCLONE NAMES for the NORTHWEST PACIFIC BASIN
Beginning in 2000 tropical storms and typhoons forming in the North
Pacific west of the Dateline were assigned names by JMA taken from a
new list of Asian names contributed by fourteen nations and territories
from the western Pacific and eastern Asia. Names are not allocated
in alphabetical order and the majority are not personal names--instead
names of animals, plants, fictional characters, descriptive adjectives,
places--even foods--are utilized. The entire list consists of 140
names and all names will be used before any are repeated. The last
name assigned in 2000 was Soulik in late December (which continued a
few days into January). The next tropical storm in the region will be
named Cimaron--the name of a Philippine wild ox.
The next 36 names on the list are (** indicates name has already
been assigned in 2001):
Cimaron Usagi Lekima Mitag
Chebi Pabuk Krosa Hagibis
Durian Wutip Haiyan Noguri
Utor Sepat Podul Ramasoon
Trami Fitow Lingling Chataan
Kong-rey Danas Kajiki Halong
Yutu Nari Faxai Nakri
Toraji Vipa Vamei Fengshen
Man-yi Francisco Tapah Kalmaegi
Since 1963 PAGASA has independently named tropical cyclones forming
in the Philippines' AOR--from 115E to 135E and from 5N to 25N (except
for a portion of the northwestern corner of the above region). Even
though the Philippines contributed ten names to the international list
of typhoon names, PAGASA still continues to assign their own names for
local use within the Philippines. It is felt that familiar names are
more easily remembered in the rural areas and that having a PAGASA-
assigned name helps to underscore the fact that the cyclone is within
PAGASA's AOR and potentially a threat to the Philippines. Another
consideration may be PAGASA's desire to assign a name when a system is
first classified as a tropical depression. Since tropical and/or
monsoon depressions can bring very heavy rainfall to the nation which
often results in disastrous flooding, the weather service feels that
assigning a name helps to enhance public attention given to a system.
Beginning with 2001 PAGASA will be using new sets of cyclone names.
These will not all end in "ng" as did the older names. Four sets of
25 names will be rotated annually; thus, the set for 2001 will be
re-used in 2005. In case more than 25 systems are named in one
season, an auxiliary set will be used. PAGASA names for 2001 are
(** indicates name has already been assigned in 2001):
Auring ** Jolina Roleta
Barok Kiko Sibak
Crising Labuyo Talahib
Darna Maring Ubbeng
Emong Nanang Vinta
Feria Ondoy Wilma
Gorio Pabling Yaning
Huaning Quedan Zuma
Isang
In the unlikely event that the list is exhausted, the following
names would be allocated as needed: Alamid, Bruno, Conching, Dolor,
Ekis, Fuerza, Gimbal, Hampas, Isko, and Juego.
**** Index to Feature of the Month Articles for 2000 ****
May - WHATEVER HAPPENED TO THE NEUTERCANE?
Jun - A SOURCE FOR STATE AND LOCAL HURRICANE HISTORIES
Jul - SEASONAL STATISTICS FOR THE EASTERN NORTH PACIFIC
Aug - MONTHLY STATISTICS FOR THE EASTERN NORTH PACIFIC
Sep - SEASONAL STATISTICS FOR THE CENTRAL NORTH PACIFIC
(also SOUTHERN HEMISPHERE TROPICAL CYCLONE NAMES)
Oct - ATLANTIC SUBTROPICAL SYSTEMS OF 2000 (Part 1)
Nov - ATLANTIC SUBTROPICAL SYSTEMS OF 2000 (Part 2)
Dec - ATLANTIC SUBTROPICAL SYSTEMS OF 2000 (Part 3)
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ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for January: No tropical cyclones
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NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for January: No tropical cyclones
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NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for January: No tropical cyclones
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NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for January: No tropical cyclones
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SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for January: 1 tropical depression
3 tropical cyclones (hurricanes)
The primary sources of information upon which the narrative is based
are the warnings issued by the TCWC on La Reunion Island, associated
with Meteo France, which is the RSMC for the Southwest Indian Ocean
basin. However, cyclones in this region are named by the sub-regional
centres on Mauritius and Madagascar with longitude 55E as the dividing
line between their respective areas. La Reunion only advises these
centres regarding the intensity of tropical systems. References to
sustained winds should be understood as implying a 10-min averaging
period unless otherwise stated. In the accompanying tracks file
some position comparisons have been made with JTWC's positions, and
warnings from JTWC were used as a source of 1-min avg MSW estimates.
Southwest Indian Ocean Tropical Activity for January
----------------------------------------------------
Most low-latitude tropical cyclones in the Southern Hemisphere form
in the monsoon trough, especially at times when impulses of strong
monsoonal westerlies, enhanced convection, and lowered atmospheric
pressure propagate eastward across the tropics. Known as Madden-
Julian Oscillations (MJOs), they also help to trigger the formation of
most North Indian Ocean cyclones and many Northwest Pacific basin
storms. One weaker impulse apparently moved across the South Indian
Ocean in November, leading to the formation of a rather weak but
enduring depression in the central South Indian. Likely this same
MJO was instrumental in the formation of Severe Tropical Cyclone Sam
and some weaker tropical LOWs near northern Australia in December, and
also possibly was in part responsible for Typhoon Soulik's development
east of the southernmost Philippines in late December.
Following Tropical Depression #2 (TC-02S per JTWC), the Southwest
Indian basin lay quiet until the very end of December. However,
things started popping after the new year had begun. Three tropical
cyclones formed in the western and central regions of the basin within
the first 2 1/2 weeks of January. All three became respectable
tropical cyclones with Ando and Charly reaching a maximum 10-min avg
MSW of 100 kts or greater. (JTWC estimated that Bindu also reached
115 kts, but La Reunion's highest MSW for Bindu was 80 kts.) Each
of the two latter cyclones formed successively eastward of the previous
one's genesis location. Fortunately, none of the Southwest Indian
cyclones made landfall, although Tropical Cyclone Ando passed close
enough to Mauritius and La Reunion to pose a significant threat.
While Tropical Cyclone Charly was reaching its peak intensity far
to the east of Mauritius, another tropical depression (#6) formed a
short distance east of central Madagascar. This system drifted
erratically for a couple of days (22-23 January) and then moved
west-southwestward to near the southeastern coastal regions of the
island as it weakened on the 24th. While La Reunion estimated the
peak 10-min avg MSW at 30 kts, JTWC never issued any warnings on this
system (although a Formation Alert was issued at 24/0100 UTC).
The author noticed a press report which stated that six deaths in
Mozambique were attributed to flooding caused by a tropical storm on
23-25 January. I wrote and asked Philippe Caroff about this. Philippe
replied and informed me that the Mozambique flooding was due to a weak
LOW which moved into the area on the 23rd. The LOW was too weak to
justify warnings but it was mentioned in the daily STWOs issued by RSMC
La Reunion. After making landfall the LOW produced some very active
convection over land. Another very weak LOW moved into Mozambique on
4 February, interacted with a weak trough and cold front to the south,
and became quasi-stationary, thereby increasing the likelihood of
continued heavy rainfall in the flood-stricken areas. (A special
thanks to Philippe for sending me the information on these systems.)
Tropical Cyclone Ando (TC-04S / MFR #3)
31 December - 10 January
----------------------------------------
Although starting late, the tropical cyclone season in the Southwest
Indian Ocean came in with a bang with three rather intense tropical
cyclones forming within the first three weeks of January. (Strangely,
after this outburst, except for a couple of tropical depressions, the
basin was to remain quiet until the second week of March.) The
beginnings of Ando can be traced to an area of convection which formed
on 30 December roughly 300 nm west-southwest of Diego Garcia. The
disturbed area was embedded in a band of convection spanning much of
the South Indian Ocean. A 30/1800 UTC surface analysis indicated that
a LLCC might be forming beneath the convection. JTWC rated the
potential for development as Fair in a STWO issued at 0100 UTC on the
31st.
La Reunion (MFR) issued the first tropical disturbance bulletin on
the system at 1200 UTC on 31 December, designating it as Tropical
Disturbance #3. The disturbance moved generally westward over the next
couple of days, remaining weak but slowly improving in organization.
JTWC issued a Formation Alert at 0930 UTC on 2 January, noting that
the disturbance showed improved organization with increasing convective
banding. A SSM/I pass at 02/0440 UTC depicted a partially-exposed LLCC
east of the deepest convection. The system was located under the
subtropical ridge axis with good outflow aloft. MFR upgraded the
disturbance to a tropical depression at 1200 UTC, and at 1800 UTC JTWC
initiated warnings on TC-02S with 35-kt winds. At the same time the
Mauritius TCWC upgraded the depression to Tropical Storm Ando, located
about 250 nm east-southeast of the island of Agalega. Satellite
imagery revealed that virtually all the convection at the time was
located in the northern semicircle of the storm. In the 24 hours
ending at 03/0600 UTC Agalega recorded 108 mm of rain; the January
average is 150 mm.
Once the system reached tropical storm intensity, however, it began
to intensify rather rapidly. A TRMM pass at 03/0620 UTC depicted a
developing eye with the primary convective band wrapping into the LLCC
from the northwest; however, there was still very little convection in
the storm's southern semicircle. JTWC upped the MSW estimate to
60 kts at 0600 UTC and MFR increased the maximum 10-min avg wind to
60 kts six hours later. By 1800 UTC convection had improved in all
quadrants and JTWC estimated the MSW at 75 kts. Ando by this time was
moving southwestward into a weakness in the subtropical ridge caused
by an approaching mid-latitude trough. At 04/0000 UTC MFR upgraded the
storm's intensity to 65 kts, making Ando the first tropical cyclone
(hurricane) of the season. Ando was then centered roughly 175 nm
southeast of Agalega.
By 1800 UTC on 4 January Ando had become a rather impressive cyclone
sporting a small 10-nm diameter eye. JTWC upped the 1-min avg MSW
estimate to 115 kts and MFR increased the peak 10-min avg sustained
wind estimate to 90 kts. This represents reasonably good agreement
between the two agencies, implying a difference of only 0.5 CI-number
(6.0 vs 5.5). At 1800 UTC Tropical Cyclone Ando's eye was located
approximately 150 nm east-northeast of Tromelin Island, and by 0600 UTC
on the 5th had approached to within 75 nm of the island (to the east-
southeast). I received a report from Patrick Hoareau which stated
that sustained winds (presumably a 10-min avg) of 50 kts were recorded
on Tromelin with higher gusts. I do not know the time the observation
was made.
The cyclone maintained its intensity for about 18 hours, but at
05/1800 UTC there was a more substantial difference between MFR's and
JTWC's estimated MSW values. At that time JTWC increased their 1-min
avg MSW estimate to 125 kts (based on CI-numbers of 6.0 and 6.5) while
MFR lowered their 10-min avg MSW to 85 kts (based on a CI-number of
5.0 and a T-number of 5.5). The storm at this time displayed
concentric eyewalls, so this may have been a consideration in the
slight reduction in intensity reported by MFR. However, MFR had
brought their 10-min avg MSW estimate up to 100 kts by 06/0600 UTC
where it remained for 18 hours. (This would have been based on a
CI-number of 6.0.)
At 1800 UTC on the 5th Tropical Cyclone Ando was centered about
215 nm northwest of Mauritius, moving slowly south-southwestward, and
by 1200 UTC on 6 January was located about 230 nm due west of the
island. The cyclone was at its peak intensity of 100 kts (125 kts per
JTWC) and displayed a 25-nm round eye surrounded by intense convection
and supported by an impressive outflow. Gales covered an area over
200 nm in diameter and 50-kt winds extended outward more than 60-nm
from the center. According to Patrick Hoareau, Ando was perhaps the
strongest tropical cyclone (based on JTWC's Best Track data) to have
occurred so far south and west in the Indian Ocean. All other cyclones
which reaced a 1-min avg MSW of 125 kts west of longitude 60E were
located farther north. At 06/1800 UTC Ando was centered about 135 nm
west of Reunion Island, still carrying 100-kt winds (JTWC's 1-min avg
MSW was down slightly to 115 kts) around an 18-nm irregular eye. At
1800 UTC St. Denis reported sustained winds of 20 kts from the east-
northeast. However, gusts exceeding hurricane force were recorded
at higher elevations on the island. At La Plaine des Cafres (altitude
1200 m) a peak gust of 72 kts was recorded. Bellecombe, at an
altitude of 2200 m, recorded a peak gust of 84 kts. The same site
measured 1255 mm of rain in the 48 hours from 05/0300 to 07/0300 UTC.
(Thanks to Patrick Hoareau for sending me this information.)
After reaching its peak intensity around 0600 UTC on 6 January, Ando
weakened slowly for about 36 hours before beginning to rapidly decline
in intensity. At 07/0600 UTC the maximum 10-min avg winds were being
reported at 90 kts by MFR while JTWC still estimated the 1-min avg MSW
at 115 kts. The cyclone was still moving within a weakness in the
subtropical ridge created by a slow-moving mid-latitude trough. By
1800 UTC on the 7th the eye had become cloud-filled and deep convection
was confined mainly to the southeastern quadrant. MFR and JTWC lowered
their MSW estimates to 80 kts and 105 kts, respectively. By 0600 UTC
on 8 January Ando had begun to weaken rapidly. A trough west of the
storm was causing an increase in vertical shear, resulting in the LLCC
becoming partially-exposed. MFR dropped the intensity to 70 kts at
0600 UTC and further downgraded Ando to a 55-kt tropical storm six
hours later. On the 9th the weakening storm began to track southward
and later turned to the south-southeast as it began extratropical
transition on the 10th. By 1800 UTC on the 9th the center was fully-
exposed with the remaining convection sheared to the southeast. JTWC
decreased their MSW estimate to 30 kts at 09/1800 UTC but MFR estimated
that the winds remained above gale force as Ando transformed into an
extratropical cyclone. The final warning (by both agencies) was issued
at 0600 UTC on 10 January with the center located roughly 600 nm south-
southwest of Reunion. The system was rapidly becoming extratropical
as a strong warm front and weaker cold front developed near the center.
Tropical Cyclone Bindu (TC-05S / MFR #4)
4 - 17 January
-----------------------------------------
Even as Ando was just being named as a tropical storm, another area
of convection was developing approximately 630 nm southwest of Sumatra
which was destined to become the season's second tropical cyclone.
JTWC issued a STWO at 1100 UTC on the 2nd, noting that the disturbance
displayed a weakly-curved convective band with a possible LLCC north
of the band. The weak LOW moved westward and by 03/1800 UTC had
moved west of longitude 90E into the Southwest Indian Ocean basin.
Convection had weakened but a QuikScat pass indicated the continued
presence of a LLCC. Convection began to re-establish itself
around the LLCC on the 4th and MFR initiated bulletins on Tropical
Disturbance #4 at 04/0600 UTC. The 10-min avg MSW was estimated at
25 kts, although winds to 30 kts were forecast for limited areas in
the southern semicircle. The center of the LOW was estimated to be
deep in the tropics about 1000 nm east of Diego Garcia.
The system continued to move westward over the next couple of days,
gradually becoming better organized. The disturbance had previously
been moving along the near-equatorial trough, but by the 5th was moving
on the equatorward side of an upper-level ridge axis. JTWC upgraded
the development potential to Fair at 05/1800 UTC and issued a Formation
Alert at 06/0000 UTC due to increasing organization of deep convection
near the LLCC over the previous six hours. However, the convection
was not over the LLCC--a 06/1521 UTC SSM/I pass depicted a fully-
exposed LLCC approximately 100 nm east of the deep convection. JTWC
issued a second Formation Alert at 07/0000 UTC, and MFR upgraded the
disturbance to a tropical depression at 0600 UTC, located about 350 nm
southeast of Diego Garcia.
A SSM/I pass at 07/1614 UTC depicted a convective banding feature
developing near the LLCC, so JTWC issued the first warning on TC-05S
at 1800 UTC. The initial warning intensity was estimated at 35 kts,
based on satellite estimates of 30 and 35 kts. At 0000 UTC on
8 January the Mauritius TCWC upgraded the depression to Tropical Storm
Bindu. Bindu's center was located approximately 300 nm south-southeast
of Diego Garcia, and the storm had taken an abrupt turn toward the
south-southwest under the steering influence of a mid-level ridge
located to the southeast.
At 08/0600 UTC Tropical Storm Bindu was tracking south-southwestward
and intensifying. Satellite imagery revealed improving organization of
convective banding and also increasingly better outflow. JTWC upped
their MSW estimate to 55 kts at 0600 UTC, and MFR increased the 10-min
avg MSW to 60 kts at 1200 UTC and to 65 kts at 09/0000 UTC when Bindu
was centered approximately 500 nm south of Diego Garcia. The cyclone
was forecast to continue moving on its south-southwesterly track for
the next 36 hours under the steering influence of a mid-level ridge to
the system's southeast. After that the storm was forecast to turn to
a more westerly track as a ridge to the south strengthened. Tropical
Cyclone Bindu continued to slowly strengthen on the 9th as it moved
slowly westward--the anticipated westward turn occurring a little
earlier than initially forecast. At 0600 UTC satellite imagery showed
a 10-nm ragged eye with the deep convection located on the eastern side
of the center.
By 1200 UTC on the 9th Bindu had reached an initial peak intensity
of 75 kts which it maintained for 18 hours before some weakening
occurred. (JTWC's estimated 1-min avg MSW reached 90 kts at 1800 UTC.)
The cyclone by now was essentially stationary, having entered a region
of weak steering flow. On 10 January the storm weakened substantially
as it encountered increased vertical shear. A 200-mb analysis revealed
moderate upper-level east-southeasterlies over the region. A SSM/I
pass at 10/1610 UTC depicted a partially-exposed LLCC with associated
deep convection displaced over the northern semicircle--the southern
half of the storm was virtually convection-free. MFR lowered the
10-min avg MSW estimate to a minimum of 55 kts at 10/1800 UTC but
bumped it back up to 60 kts six hours later. JTWC's 1-min avg MSW
values bottomed out at 65 kts at 1800 UTC and remained there until
0600 UTC on the 12th. Dvorak intensity estimates during this period
were generally running around 55 to 65 kts.
By 0600 UTC on 11 January 200-mb analysis indicated that upper-level
winds over the storm had weakened, and Bindu slowly staged a comeback.
MFR re-classified Bindu as a tropical cyclone with 70-kt winds at
1200 UTC when the center was located about 475 nm east-northeast of
Rodrigues Island. (JTWC's MSW estimate remained at 65 kts at this
time.) At 0600 UTC on the 12th the cyclone's center was located about
360 nm east-northeast of Port Mathurin on Rodrigues and moving west-
southwestward at 4 kts. Bindu at this time displayed a 13-nm ragged,
cloud-filled eye, and a 12/0019 UTC TRMM pass depicted a well-defined
primary band wrapping into the center from the south while a large
feeder band was evident over the eastern half of the system. The
building mid-level ridge to the south had resulted in the storm's
west-southwesterly track.
JTWC upped their 1-min avg MSW estimate to 90 kts at 12/0600 UTC and
to the peak value of 115 kts at 1800 UTC when Bindu was centered
approximately 350 nm east-northeast of Port Mathurin. MFR increased
the official 10-min avg MSW to its maximum value for the storm's
history--80 kts--at the same time. The cyclone had continued to
intensify, and had a 15-nm ragged, cloud-filled eye with deepening
convection in the eyewall. Bindu at this time had turned to a
southerly track and was moving south at 5 kts. In the 1800 UTC warning
JTWC noted that CI-numbers ranged from 5.0 to 6.5. JTWC used a CI-
number of 6.0 as the basis for their 115-kt MSW estimate, whereas
MFR based their 80-kt estimate on a CI-number of 5.0 (90 kts 1-min
avg converted to 80-kts 10-min avg). At its peak Tropical Cyclone
Bindu caused gales over 80 nm from its center and over 150 nm in the
southeastern quadrant while 50-kt winds extended out 40-60 nm from the
center. (See note below.)
At 0600 UTC on 13 January Bindu was still maintaining its intensity
but the first signs of impending weakening could be seen. A slot of
dry air was wrapping into the cyclone's center and CIMSS vertical shear
charts indicated moderate shear over Bindu. An upper-level LOW south-
west of the storm was enhancing upper-level flow plus causing
subsidence of dry air into the cyclone's inflow. Twenty-four hours
later the shear had increased and Bindu had weakened significantly
with the center exposed and convection sheared to the south. Winds
were down to 70 kts at 14/0600 UTC (per both warning centres), and
further down to 55 kts by 1800 UTC. The weakening storm was then
located about 270 nm east of Rodrigues and moving southwestward at
4 kts.
The storm's intensity had further declined to 45 kts by 0600 UTC on
the 15th but remained pegged there for about 24 hours. At 15/1800 UTC
Bindu's center was located about 75 nm southeast of Port Mathurin.
Animated satellite imagery indicated that the LLCC was on the north-
eastern edge of the deep convection, and a 15/1305 UTC QuikScat pass
showed an extensive area of convergent flow and gale-force winds south
of the center. The weakening trend was resumed on the 16th and Bindu
was downgraded to a weakening depression at 1200 UTC. A 06/0347 SSM/I
pass depicted a fully-exposed LLCC displaced approximately 90 nm north-
west of the deep convection. The final bulletin on Bindu from MFR was
issued at 0600 UTC on 17 January and placed the center roughly 250 nm
south-southeast of Mauritius. Central winds were estimated at only
25 kts, but winds of up to 30 kts were forecast for waters up to
120 nm from the center in the southwest quadrant and up to 300 nm in
the southeast quadrant.
NOTE: After the above report was almost completed, I received an
e-mail from Patrick Hoareau which explains the considerable discrepancy
in the peak intensity for Bindu as reported by MFR and JTWC at
12/1800 UTC. The 115-kt MSW estimated by JTWC at that hour was based
on the satellite bulletin issued at 12/1730 UTC. The CI-number and
Final T-number were both given as 6.5, but the remarks indicated that
the Model-expected T-number was 5.5. The next satellite bulletin from
JTWC at 12/2330 UTC reported T5.0/5.5, and the remarks indicated that
the 12/1730 UTC satellite image had been corrupted. Therefore, it
seems likely that the 115-kt peak MSW was too high and will likely be
lowered in the Best Track.
Tropical Cyclone Charly (TC-06S / MFR #5)
17 - 26 January
------------------------------------------
The third intense Southwest Indian tropical cyclone of January
formed in the eastern reaches of the basin and followed a track roughly
parallel to that taken by the previous tropical cyclone, Bindu. Based
on La Reunion's warnings, Charly was a substantially more intense storm
than Bindu, but JTWC estimated a slightly higher peak MSW (1-min avg)
for Bindu. Whereas the pre-Bindu disturbance had taken about 5 or 6
days to reach tropical storm intensity after it was first mentioned
in any STWOs, the pre-Charly system developed even more slowly--over a
week elapsed after the initial area of convection developed before
Mauritius upgraded the system to Tropical Storm Charly.
JTWC issued a STWO on 11 January which mentioned that an area of
convection had developed approximately 670 nm southwest of Sumatra (in
the western reaches of the Australian Region). Animated visible and
infrared imagery showed that the areal coverage of convection had
increased during the previous twelve hours, and synoptic data indicated
a developing LLCC in the near-equatorial trough. The LOW remained
quasi-stationary in the same general area east of longitude 90E for
several days. JTWC upgraded the potential for development to Fair on
the 12th as deep convection increased near the LLCC and a 200-mb
analysis indicated improving diffluence aloft. The disturbance more or
less held its own through the 13th but weakened some on the 14th. JTWC
downgraded the development potential to Poor at 14/0000 UTC, and a STWO
issued at 1800 UTC remarked that convection was unorganized about a
weak, elongated LLCC located in a weak to moderate vertical shear
environment.
By 1800 UTC on 15 January the disturbance, which was by this time
centered about 290 nm west of Cocos Island, was once more showing some
tentative signs of development: convective organization was improving
with some curved bands noted south of the LLCC, a 15/1128 UTC QuikScat
pass showed an elongated but well-defined LLCC, and a 200-mb analysis
indicated that the center was now under the subtropical ridge axis;
therefore, JTWC once more assigned a Fair development potential to the
system. The disturbance began to move steadily to the west and
had crossed longitude 90E into the Southwest Indian basin by 1800 UTC
on the 16th. MFR issued the first bulletin on Tropical Disturbance #5
at 1800 UTC on 17 January, locating the center about 850 nm east-
southeast of Diego Garcia. JTWC issued a Formation Alert at 1200 UTC
on the 18th. The disturbance exhibited a partially-exposed LLCC with
convection sheared to the southwest, but some convection was beginning
to re-establish itself over the LLCC. At the time synoptic reports
and QuikScat data indicated a well-defined 25-kt circulation.
MFR upgraded the disturbance to a 30-kt tropical depression at 1800
UTC, and JTWC issued a second Formation Alert at 19/0600 UTC. The LLCC
had begun to move under the convection and a recent QuikScat pass
indicated increasing surface windspeeds; also, the outflow over the
system was improving. After moving westward to a point several hundred
miles west of longitude 90E, the depression came to a halt on the 17th
and remained quasi-stationary through the 19th. At 19/1200 UTC the
Mauritius TCWC upgraded the depression to a tropical storm and assigned
the name Charly. Charly was then centered about 825 nm east-southeast
of Diego Garcia. JTWC followed with their first warning on Charly at
1800 UTC, assigning a 1-min avg MSW estimate of 40 kts; the 10-min avg
MSW was also estimated at 40 kts. The young tropical storm was moving
southwestward at 7 kts, and this motion soon turned into a more west-
southwesterly track which the cyclone followed throughout most of its
life. A low- to mid-level HIGH south-southeast of Charly was
dominating the steering flow at this time.
Conditions were becoming increasingly favorable for intensification
with a northwesterly jet enhancing outflow, and by 0600 UTC on the 20th
Charly had moved under an upper-level ridge axis. The storm began to
steadily intensify with winds increasing to 55 kts (per both agencies)
at 20/0600 UTC. By 1800 UTC Charly was centered about 1000 nm east-
northeast of Port Mathurin on Rodrigues Island with 10-min avg MSW
estimated at 60 kts. JTWC increased their MSW estimate to 65 kts at
1800 UTC and to 75 kts at 21/0600 UTC, but MFR did not upgrade Charly
to tropical cyclone status with 65-kt winds until 1200 UTC on the 21st
when the storm was located about 800 nm east-northeast of Rodrigues.
Charly was following basically a west-southwesterly track, although it
jogged a little more to the west on the 21st. By 1800 UTC animated
infrared imagery was depicting a 29-nm irregular eye. MFR increased
the 10-min avg wind to 80 kts and JTWC upped their MSW estimate to
90 kts.
Tropical Cyclone Charly continued to intensify and reached its peak
intensity of 105 kts at 1800 UTC on 22 January when it was centered
approximately 500 nm east of Rodrigues. Deep convection surrounded
an eye 20 nm in diameter, and a CIMSS upper-level analysis indicated
that the system still remained underneath an upper-level ridge. The
105-kt intensity was reported by both MFR and JTWC, but a 10-min avg
wind of 105 kts would equate to a 1-min avg MSW of 120 kts, so in this
case La Reunion's estimate was the more liberal. The gale radii
reported by MFR was also larger than JTWC's: 190 nm in the southern
semicircle and 115 nm elsewhere as compared to 120 nm in the south-
eastern quadrant and 80 nm elsewhere per JTWC. By 0600 UTC on the
23rd Charly had moved southwestward at 12 kts and was located about
390 nm east of Port Mathurin. MFR maintained the storm's intensity
at 105 kts through this warning cycle, but JTWC decreased their 1-min
avg MSW estimate to 100 kts; the eye had filled and a decrease in
convection was noted in the southeastern quadrant.
Of the three January cyclones in the Southwest Indian Ocean, Charly
weakened the most rapidly after reaching its peak intensity. At
0600 UTC on 23 January MFR was still reporting the sustained winds at
the peak value of 105 kts with an estimated CP of 925 mb--24 hours
later Charly had been downgraded to a 55-kt tropical storm. A CIMSS
upper-level wind analysis indicated that the cyclone had moved south
of the upper-level ridge and into a region of moderate vertical shear.
In addition to this, drier air was being entrained into the system from
the west. Shortly before 1200 UTC on the 24th the weakening storm
passed about 200 nm south of Rodrigues Island. JTWC decreased their
1-min avg MSW estimate to 45 kts at 1800 UTC, but MFR maintained the
storm at 50 kts in their warnings. A 24/1712 UTC SSM/I pass indicated
a fully-exposed LLCC with the remaining deep convection sheared
approximately 150 nm southeast of the center.
Both warning centres downgraded Charly to a weakening depression at
25/1800 UTC. The center was fully-exposed with some isolated
convection well to the east. A 25/1353 UTC QuikScat pass indicated
that the LLCC was elongating with the stronger winds in the poleward
semicircle. The final bulletin issued by La Reunion at 26/1200 UTC
placed the weakening center about 280 nm south-southeast of Reunion.
Winds near the center were estimated at only 25 kts, but some local
winds to 30 kts were occurring up to 180 nm from the center in the
southern semicircle.
***********************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for January: 1 tropical LOW
1 tropical cyclone
NOTE: The primary sources of information for Australian Region
tropical cyclones are the warnings and bulletins issued by the three
TCWC's at Perth, Darwin, and Brisbane. Information gleaned from
JTWC's warnings was used as a supplement for times when it was
impossible to obtain Australian bulletins and for comparison purposes.
References to sustained winds should be understood as being based on a
10-min averaging period unless otherwise noted.
A description of the Australian Cyclone Severity Scale, which is
alluded to in the narrative below, can be found in Chris Landsea's FAQ
on HRD's website:
http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqD.html#D2>
or on Michael Bath's Australian Severe Weather site:
http://australiansevereweather.com/cyclones/history.htm>
Carl Smith, a cyclone enthusiast who lives on Queensland's Gold
Coast, has a website which contains a great amount of information on
tropical cyclones. The URL is: http://www.ace-net.com.au/~carls/>.
Carl also sends me reports he compiles on the tropical cyclones and
LOWs in the Australian Region from which I often extract information.
Northwest Australia/Southeast Indian Ocean
Tropical Activity for January
------------------------------------------
Active monsoonal conditions began to reach the Australian region
late in January. Tropical Cyclone Terri was named on the 29th and
was the first tropical cyclone in the normally rather active waters
off Western Australia since Cyclone Sam in early December. Terri did
make landfall in Western Australia but did not reach severe cyclone
status (hurricane force). (The monsoon subsequently intensified
during February and spawned several tropical cyclones in northern
Australian waters during the month.)
One other tropical LOW formed during January north of the Top End
of the Northern Territory. On 7 January the Darwin TCWC issued an
advice on a weak tropical LOW which had formed about 165 nm north-
northeast of Darwin. Over the next couple of days the LOW moved slowly
in a general southerly direction and crossed the coast around 0630 UTC
on the 9th at a point about 30 km east of Point Stuart or about 140 km
(75 nm) east-northeast of Darwin. The advices from Darwin estimated
the peak gusts at 80 kph (43 kts), which converts to a peak 10-min avg
sustained wind of about 30 kts. After moving inland the LOW weakened
into a rain depression. It was believed that there was a chance the
system might move westward over the Timor Sea and intensify, but the
LOW remained over land and gradually weakened. (JTWC did not issue
any warnings on this system.)
Tropical Cyclone Terri (TC-07S)
28 - 31 January
--------------------------------
After a month-and-a-half of inactivity (following Tropical Cyclone
Sam), tropical cyclone activity returned to the waters of the Southeast
Indian Ocean off Western Australia. The TWO for northwestern Australia
issued by Perth on 27 January (around 0400 UTC) indicated that a
tropical LOW had formed inland over the Kimberley region well southeast
of Broome. The LOW was causing widespread rain and thunderstorms in
the area and was expected to move off the Kimberley coast within a
couple of days and possibly develop into a tropical cyclone. Also on
the 27th JTWC mentioned the disturbance in a STWO, noting that animated
satellite imagery indicated strong convection organizing around a
possible LLCC. The highest winds were estimated at 20-25 kts and the
LOW was given a Fair potential for development.
JTWC issued a Formation Alert at 28/0100 UTC--the LOW was becoming
better organized although the loosely-defined and partially-exposed
LLCC was still centered inland over the Kimberley area. Satellite-
derived wind products from CIMSS indicated a favorable upper-level
environment for development. Perth began issuing High Seas warnings
at 0400 UTC on the 28th with the LOW centered near the coast about
170 nm north-northeast of Broome. The LOW moved westward, gradually
pulling away from the Australian coastline and increasing in intensity.
JTWC initiated warnings on TC-07S at 0600 UTC on 29 January, estimating
the MSW (1-min avg) at 30 kts (based on CI estimates of 25 and 30 kts).
A mid-level ridge to the south was forecast to keep the system moving
on a westerly course. A 29/1222 UTC TRMM pass revealed that the LLCC
was fully-exposed southeast of the deep convection. Perth upgraded
the LOW to Tropical Cyclone Terri at 1600 UTC but JTWC held their
intensity estimate to 30 kts in the 1800 UTC warning. At 30/0100 UTC
Perth issued an intermediate warning which relocated Terri's center
about 40 nm east of the previous warning position. Based on the peak
gusts given in the corresponding public advice, the maximum 10-min avg
sustained wind was estimated to be in the vicinity of 40 kts. The
cyclone's center at this time was located about 135 nm west-northwest
of Broome, moving southwestward at 5 kts.
JTWC increased their MSW estimate to 35 kts at 0600 UTC on the 30th
as animated satellite imagery showed deep convection located slightly
to the west of the LLCC. Perth upped the 10-min avg MSW to 55 kts at
1000 UTC as Terri moved southwestward off the Western Australian
coastline. By 1600 UTC the cyclone reached the westernmost point of
its track (about 190 nm west-southwest of Broome), thereafter turning
south-southeastward toward the coast. JTWC estimated the 1-min avg MSW
at 45 kts at 1800 UTC, but at 2200 UTC Perth increased their reported
10-min avg MSW to 60 kts with the CP estimated at 975 mb. Tropical
Cyclone Terri made landfall just east of Point Poissonnier near Pardoo
at approximately 0130 UTC on the 31st as a Category 2 cyclone on the
Australian Cyclone Severity Scale. Synoptic data and TRMM passes
indicated that the cyclone moved ashore packing peak 10-min avg
sustained winds of 60 kts, which would equate to a 65 to 70-kt 1-min
avg MSW. The JTWC warning at 31/0600 UTC, issued about four hours
after Terri had moved inland, still reported the MSW at 55 kts. Within
a few hours after making landfall, Terri began to weaken rapidly as it
accelerated south-southeastward across the Great Sandy Desert.
According to Andrew Burton, a meteorologist at the Perth TCWC, the
center of Tropical Cyclone Terri crossed the coast around 0130 UTC on
31 January about 30 km east of Pardoo. At 0100 UTC Pardoo reported
10-min avg winds of 55 kts from the south-southeast with an attendant
MSLP of 984 mb. At 0400 UTC Pardoo reported a pressure of 991 mb
and west-northwesterly winds of 60 kts. Andrew points out that there
is a slight question mark on the 60-kt observation in that it is
possible it represents the peak wind strength rather than a 10-min
mean. However, since this is difficult to confirm, the 60-kt reading
will likely be accepted as the highest wind speed recorded. Bedout
Island AWS (WMO 94310) recorded a maximum wind speed of 52 kts from
the south-southwest at 0000 UTC with a MSLP of 988 mb. The pressure
there was 984 mb at 30/2200 UTC with the wind southeasterly at 43 kts.
The author has learned of no casualties or damage resulting from
Tropical Cyclone Terri.
***********************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for January: 2 non-tropical or hybrid LOWs
Northeast Australia/Coral Sea
Tropical Activity for January
-----------------------------
While no named tropical cyclones or active purely tropical LOWs
formed between 135E and 160E during January, a couple of non-tropical
LOWs which were likely somewhat hybrid in nature formed near the
coasts of southeastern Queensland and northeastern New South Wales
and brought strong winds and quite a bit of severe weather to
portions of those Australian states. Jeff Callaghan of the Brisbane
TCWC has sent me reports on these two LOWs, plus, I have some
additional information from Carl Smith and from some press reports.
(1) 18 - 19 January - A mid- to upper-level trough developed an
involuted pattern, forming a 500-mb cut-off LOW east of Brisbane by
1200 UTC on 18 January. Severe thunderstorms preceded this in northern
New South Wales and southeastern Queensland. Casino in New South Wales
was badly damaged, and as the storms moved towards Queensland, Evans
Head AWS (WMO 94598) recorded a 73-kt gust. Around 17/1300 UTC severe
storms damaged many houses in the southern suburbs of Brisbane and
adjacent rural areas. Around 1730 UTC (3:30 am local time) hail
between golfball and tennis ball size hit the northern suburbs of
Brisbane. A third wave of storms hit Brisbane and the Gold Coast
around 2130 UTC on the 17th (7:30 am local time) causing damage to many
houses. A broad, open LOW then developed east of Brisbane with maximum
10-min avg winds of 130/48 kts recorded at Cape Moreton (WMO 94594)
at 1234 UTC on the 19th. Pressure rises along the coast south of the
LOW as a HIGH moved into the Tasman Sea contributed to the development
of the gales. The gales caused damage to moored marine craft and
brought down power lines, causing blackouts (60,000 homes without power
according to a press report). Severe thunderstorms developed just
south of Townsville around 0800 UTC on the 19th under a marked upper-
level divergent area north of the upper-level trough. This caused
major damage from wind and lightning in an area not known for severe
thunderstorms and broke an Australian lightning record (2500 strikes
in an hour).
The above was Jeff's report. According to some information from
Carl Smith (who lives on the Gold Coast), Casino was belted with
baseball-sized hail and wind that ripped roofs off and smashed trees.
Carl further writes: "On the 17th-18th the Gold Coast to the Redcliffe
area of southeastern Queensland got belted by a series of supercells
over a period of more than 12 hours, starting in the late afternoon
and continuing during the night, with hail up to 10 cm (4 inches) in
diameter in places, gale-force winds, trees down all over the place,
severe damage to over 120 houses on the Gold Coast--one dead through
stepping on a fallen power line. I have never in my life seen such a
spectacular lightning display as that accompanying the supercell that
hit here at 8:30 pm (1030 UTC). It was like daylight outside and the
thunder was a continuous roar for a least an hour as it closed in and
hit with a vengeance--continuing in spectacular fashion for long
afterwards. You could have easily read a newspaper from the continuous
lightning."
Prior to the severe weather and LOW described above, severe wind-
storms had struck the Sydney area as a frontal trough moved northward
along the East Coast. Wind gusts to 60 kts caused massive damage,
uprooted trees, and left 78,000 homes without power. The severe
thunderstorms which damaged Casino so badly formed in association with
this frontal trough. A press report dated 18 January stated that the
total damage from the severe storms which had affected Australia during
the previous ten days amounted to $80 million (Australian).
(3) 31 January - 2 February - Another mid- to upper-level involuted
trough began forming over New South Wales on 31 January, leading to
the formation of a 500-mb LOW just to the west of Brisbane by 1200 UTC
on 1 February. The MSL reflection was a 1001-mb LOW near Rockhampton
(near the east coast on the Tropic of Capricorn). This complex LOW
extended a trough down to the Brisbane area as a large, strengthening
HIGH moved into the Tasman Sea, producing an intense pressure gradient
over southern Queensland and northern New South Wales. Winds reached
storm force on the open coast near Brisbane with Cape Moreton AWS
recording easterly storm force winds between 1553 and 1900 UTC on
1 February, the maximum 10-min avg wind being 51 kts. The gales
extended well inland into the Tablelands where Toowoomba (WMO 95551)
recorded 10-min avg winds to 38 kts at 1739 UTC on the 1st. Tenter-
field, located on the Tablelands just south of the Queensland border,
sustained widespread wind damage.
On the exposed coast the winds brought down many trees in elevated
areas and power blackouts were widespread. Seas rapidly developed with
peak wave heights reaching just over 10 metres on wave rider buoys near
Brisbane. Rainfall was very heavy with 24-hour rainfall totals in
southeastern Queensland as an example: Springbrook - 384.8 mm,
Glorious - 341 mm, and Natural Bridge - 320 mm. There was flooding
in southeastern Queensland; however, this was reduced due to a
prolonged dry period leading up to this event. However, over the
border in New South Wales there was major flooding in the Lismore area
where many people had to be evacuated. In southeastern Queensland
there were several near escapes when people drove into flooded stream
crossings and their vehicles were swept away. However, in all cases
the drivers managed to scramble to safety. One man was drowned when
he dived into a flooded river just north of Brisbane.
NOTE: A track was given in the January cyclone tracks file for the
first of these LOWs but a track was not available for the second.
Also, a special thanks is due to Jeff and Carl for the information
they supplied.
***********************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for January: No tropical cyclones
South Pacific Tropical Activity for January
-------------------------------------------
No tropical cyclones were named in the South Pacific basin east of
160E in January, this quietude following on the heels of an equally
inactive November and December (although a couple of tropical and/or
hybrid depressions formed in December). According to Steve Ready,
the last time on record the South Pacific failed to produce a tropical
cyclone by 1 February was the 1944-45 season. There have been several
cyclone-free February's noted (1943, 1952, 1985, 1995), but none of
these examples followed a cyclone-free January. In an e-mail to Steve
(and to Alipate Waqaicelua), Roger Edson mentioned that some hybrid
systems had formed east of the Dateline during the current season and,
in his opinion, had reached marginal tropical storm intensity. (Likely
one of these was Tropical Depression 03F in December.) Roger also
alluded to such a system in existence on 25 January in the southeastern
Pacific (for which he had attached an image); however, I could find no
reference to a system on this date in any daily STWO bulletins from
either Fiji or JTWC.
***********************************************************************
EXTRA FEATURE
In order to shorten the amount of typing in preparing the narrative
material, I have been in the habit of freely using abbreviations and
acronyms. I have tried to define most of these with the first usage
in a given summary, but I may have missed one now and then. Most of
these are probably understood by a majority of readers but perhaps a
few aren't clear to some. To remedy this I developed a Glossary of
Abbreviations and Acronyms which I first included in the July, 1998
summary. I don't normally include the Glossary in most months in
order to help keep them from being too long. If anyone would like to
receive a copy of the Glossary, please e-mail me and I'll be happy
to send them a copy.
***********************************************************************
AUTHOR'S NOTE: This summary should be considered a very preliminary
overview of the tropical cyclones that occur in each month. The cyclone
tracks (provided separately) will generally be based upon operational
warnings issued by the various tropical cyclone warning centers. The
information contained therein may differ somewhat from the tracking and
intensity information obtained from a "best-track" file which is based
on a detailed post-seasonal analysis of all available data. Information
on where to find official "best-track" files from the various warning
centers will be passed along from time to time.
The track files are not being sent via e-mail. They can be retrieved
in the following manner:
(a) FTP to: hrd-type42.nhc.noaa.gov [140.90.176.206]
(b) Login as: anonymous
(c) For a password use your e-mail address
(d) Go to "data" subdirectory (Type: cd data)
(e) Set file type to ASCII (Type: ascii)
(f) Transfer file (Type: get remote_file_name local_file_name )
(The files will be named with an obvious nomenclature--using
January as an example: jan01.tracks)
(g) To exit FTP, type: quit
Both the summaries and the track files are standard text files
created in DOS editor. Download to disk and use a viewer such as
Notepad or DOS editor to view the files.
The first summary in this series covered the month of October,
1997. If anyone wishes to retrieve any of the previous summaries,
they may be downloaded from the aforementioned FTP site at HRD. The
summary files are catalogued with the nomenclature: jan01.sum, for
example.
Back issues can also be obtained from the following websites
(courtesy of Michael Bath, Michael V. Padua, Tom Berg, Michael
Pitt, and Rich Henning):
http://australiasevereweather.com/cyclones/>
http://www.typhoon2000.com> OR http://www.geocities.com/taifun00/>
http://www.hurricanealley.net/>
http://www.qisfl.net/home/hurricanemike>
http://www.met.fsu.edu/gsc/Docs/Grads/henning/cyclones/>
Another website where much information about tropical cyclones may
be found is the website for the UK Meteorological Office. Their site
contains a lot of statistical information about tropical cyclones
globally on a monthly basis. The URL is:
http://www.met-office.gov.uk/sec2/sec2cyclone/sec2cyclone.html>
TROPICAL CYCLONE REPORTS AVAILABLE
JTWC now has available on its website the complete Annual Tropical
Cyclone Report (ATCR) for 2000 (1999-2000 season for the Southern
Hemisphere). Also, ATCRs for earlier years are available also.
The URL is: http://199.10.200.33/jtwc.html>
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 2000 Atlantic and Eastern North Pacific
tropical cyclones; also, preliminary storm reports for all the 2000
Atlantic and Eastern North Pacific cyclones are now available.
The URL is: http://www.nhc.noaa.gov>
Prepared by: Gary Padgett
E-mail: garyp@alaweb.com
Phone: 334-222-5327 (nights & weekends) / 850-882-2594 (weekdays)
***********************************************************************
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